The present invention relates to an air-bag, and more particularly relates to an air-bag intended to protect an occupant of a motor vehicle in the event that an accident should occur.
Many different designs of air-bag have been proposed for use in protecting passengers in motor vehicles. Some air-bags are formed using two identical sheets or layers of fabric which are simply superimposed and connected by a peripheral seam. The air-bag, before folding and inflation, can therefore be spread out to be perfectly flat. Air-bags of this type are frequently used as a driver's air-bag, the air-bag being mounted within the hub of a steering wheel. Initially the fabric layers are substantially circular and thus, when the air-bag is inflated, the air-bag has a generally spherical form.
In order to protect the occupant of the passenger seat adequately, a bag has to be provided which must move a substantial distance into the passenger compartment, since a conventional passenger bag is initially stored in a housing present in the dashboard of a vehicle, which is further from the passenger than the steering wheel is from the driver. It has therefore been the practice to utilise a pre-shaped, or three-dimensional air-bag for such an application. A typical three-dimensional passenger air-bag is made of at least three pieces of fabric which comprise two side pieces, and at least one middle piece which connects the two side pieces. Typically such an air-bag, when spread out uninflated, will partly stand up. The fabrication of such an air-bag requires much work cutting out the pieces, and also much work in sewing the pieces together. Consequently these air-bags are expensive to manufacture.
U.S. Pat. No. 5,454,594 describes a three-dimensional air-bag which is formed from two pieces of fabric which are interconnected using one continuous seam. The two pieces of fabric are not identical, and the resultant air-bag has a seam pattern which is reminiscent of that of a tennis ball. It is not practicable to cut the pieces of fabric from a single sheet of fabric without substantial wastage.
WO99/46149 discloses an air-bag made from a single element of fabric which comprises two mirror-image portions interconnected by a fold-line. Again it is difficult to cut fabric elements for use in forming air-bags of this type from a single sheet without substantial wastage of fabric.
The present invention seeks to provide an improved air-bag.
According to this invention there is provided an air-bag, the air-bag comprising two fabric elements of corresponding, but inverted design, each fabric element defining a generally rectangular region having, at one end thereof, a generally triangular extension, the extension having one side thereof substantially contiguous with one side of the rectangular region, the element having a projection extending outwardly from the other side of the rectangular region, the two elements being located adjacent each other with the rectangular regions thereof substantially superimposed, and with the projections provided on opposed sides thereof, the elements being interconnected by means of a peripheral seam, the rectangular region of one element forming a rear wall, and the rectangular region of the other element forming a front wall, the projections forming side-walls interconnecting the front wall and the rear wall, and the triangular regions being inter-engaged to form an end region of the air-bag.
Preferably each projection has a linear edge extending from the relevant side of the rectangular area at a point spaced from the end thereof, the linear edge being complemented by a terminal region which terminates substantially at a corner of the rectangular area.
In one embodiment the terminal region is curved.
Preferably the air-bag, when inflated, is substantially “drop”-shaped.
In an alternative embodiment the projection is of generally triangular form.
Conveniently the air-bag, when inflated, is generally triangular-shaped.
Preferably the air-bag is provided with a gas inlet hole formed in one of the fabric layers.
Alternatively a gas inlet hole is formed in the seam.
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: